US8187698B2ActiveUtilityPatentIndex 57
Coated cutting tool for fine to medium-rough turning of stainless steels
Est. expiryFeb 1, 2027(~0.6 yrs left)· nominal 20-yr term from priority
C23C 30/005C23C 16/403C23C 16/36C23C 16/34C23C 16/32C23C 16/30B23B 27/148Y10T428/265Y10T428/24975Y10T82/10Y10T83/9493Y10T407/27
57
PatentIndex Score
5
Cited by
6
References
20
Claims
Abstract
The present invention relates to a cutting tool insert comprising a cemented carbide body and a coating particularly useful in fine to medium-rough turning of stainless-steels. The cemented carbide body consists of a cemented carbide with a composition of 5.0-9.0 wt-% Co, 5.0-11.0 wt-% cubic carbide forming metals from group IVb, Vb and VIb of the periodic table, preferably Ti, Nb and Ta, and balance WC with a 10-30 μm essentially cubic carbide phase free and binder phase enriched surface zone. The coating comprises an MTCVD Ti(C7N) as the first layer adjacent the body having a thickness of from 2.5 to 7.0 μm, on top of which an α-Al 2 O 3 layer is present, with a thickness of between 2.0 and 5.0 μm, and a total thickness of the coating between 5.5 and 9.5 μm. The alumina layer has a (006) texture.
Claims
exact text as granted — not AI-modified1. A cutting tool insert, comprising:
a cemented carbide body that comprises 5.0-9.0 wt-% Co, 5.0-11.0 wt-% cubic carbide forming metals selected from group IVb, Vb and VIb of the periodic table and balance WC, and with a weight-ratio of Ta and Nb, when present, between 1.0-3.0 and between Ti and Nb, when present, within 0.5-1.5 and with a coercivity (Hc) of 10.0-15.0 kA/m, whereby the cemented carbide is provided with a 10-30 μm, essentially cubic carbide phase free and binder phase enriched surface zone with average binder phase content in the range 1.2-2.5 times the nominal binder phase content; and
a coating that comprises a MTCVD Ti(C,N) as a first layer adjacent the body having a thickness of from 2.5 to 7.0 μm, where the MTCVD-layer comprises an innermost TiN layer adjacent to the body with a Ti(C,N) layer on top, optionally with an additional intermediate TiN layer on top of the Ti(C,N) layer, with a thickness of 0.3-1.0 μm on top of which an α-Al 2 O 3 layer is present, with a thickness of between 2.0 and 5.0 μm and a total thickness of the coating between 5.5 and 9.5 μm, where the texture of the α-Al 2 O 3 layer is TC(006)>2.0 and where the texture coefficients (TC) for the α-Al 2 O 3 layer is determined as follows:
TC
(
hkl
)
=
I
(
hkl
)
I
0
(
hkl
)
[
1
n
∑
n
=
1
n
I
(
hkl
)
I
0
(
hkl
)
]
-
1
where
I(hkl)=intensity of the (hkl) reflection,
I 0 (hkl)=standard intensity according to JCPDS card no 46-1212, and
n=number of reflections used in the calculation, and the (hkl) reflections used are: (012), (104), (110), (006), (113), (202), (024) and (116), where TC(012), TC(110), TC(113), TC(202), TC(024) and TC(116) are all simultaneously <1 and TC(104) is the second highest texture coefficient with TC(104) between 0.5 and 2.0.
2. The cutting tool insert according to claim 1 , wherein the surface of α-Al 2 O 3 layer is wet-blasted, with roughness R a =0.5-1.0 μm.
3. A method for making a cutting tool insert, comprising:
providing a substrate made by powder metallurgical methods milling, pressing and sintering with a cemented carbide substrate with a composition of 5.0-9.0 wt-% Co, 5.0-11.0 wt-% cubic carbide forming metals selected from group IVb, Vb and VIb of the periodic table, and balance WC, and with a weight-ratio of Ta and Nb, when present, between 1.0-3.0 and between Ti and Nb, when present, within 0.5-1.5, and with a coercivity (Hc) of 10.0-15.0 kA/m, whereby the cemented carbide is provided with a 10-30 μm essentially cubic carbide phase free and binder phase enriched surface zone with average binder phase content in the range 1.2-2.5 times the nominal binder phase content, and
depositing after post sintering treatments including edge honing the cemented carbide surface a Ti(C,N) layer and optional intermediate layers, if present, by CVD, MTCVD, and combinations thereof and subsequently using a CVD process incorporating several different deposition steps to nucleate α-Al 2 O 3 at a temperature of 1000° C. in a C0 2 +CO+H 2 +N 2 gas mixture the composition of which is controlled to result in an O-potential required to achieve (006) texture and finally the α-Al 2 O 3 -layer by CVD at 1000° C.
4. A method for wet or dry fine or medium-rough turning of stainless steel, comprising cutting with a cutting tool insert of claim 1 at a cutting speed of 120-275 m/min, a cutting depth 0.5-4.5 mm and a feed of 0.1-0.45 mm/rev.
5. The cutting tool insert of claim 1 ,
wherein said cemented carbide body comprises 6.0-8.0 wt-% Co.
6. The cutting tool insert of claim 1 ,
wherein said cemented carbide body comprises 6.5-9.5 wt-% cubic carbide forming metals selected from group IVb, Vb and VIb of the periodic table.
7. The cutting tool insert of claim 1 ,
wherein said cubic carbide forming metals from group IVb, Vb and VIb of the periodic table are selected from the group consisting of Ti, Nb, Ta, and combinations thereof.
8. The cutting tool insert of claim 1 ,
wherein said weight-ratio of Ta and Nb is between 1.5-2.5.
9. The cutting tool insert of claim 1 ,
wherein said weight-ratio of Ti and Nb is between 0.8-1.2.
10. The cutting tool insert of claim 1 ,
wherein said coercivity (Hc) is 11.0-13.0 kA/m.
11. The cutting tool insert of claim 1 ,
wherein said cemented carbide is provided with a 15-25 μm essentially cubic carbide phase free and binder phase enriched surface zone with average binder phase content in the range 1.2-2.5 times the nominal binder phase content.
12. The cutting tool insert of claim 1 ,
wherein said coating comprising a MTCVD Ti(C,N) as the first layer adjacent the body having a thickness of from 3.5 to 5.0 μm.
13. The cutting tool insert of claim 1 ,
wherein said innermost TiN layer has a thickness below 0.5 μm.
14. The cutting tool insert of claim 1 ,
wherein said intermediate TiN layer on top of the Ti(C,N) layer has a thickness of 0.5-0.8 μm.
15. The cutting tool insert of claim 1 ,
wherein said α-Al 2 O 3 layer has a thickness of between 2.5 and 4.0 μm.
16. The cutting tool insert of claim 1 ,
wherein said total thickness of the coating is between 6.5 and 8.5 μm.
17. The cutting tool insert of claim 1 ,
wherein said texture of the α-Al 2 O 3 layer is TC(006)>3.
18. A cutting tool insert of claim 1 ,
wherein the surface of the α-Al 2 O 3 layer is wet-blasted, with roughness R a =0.5-0.7 μm.
19. A cutting tool insert, comprising:
a cemented carbide body comprising 5.0-9.0 wt-% Co, 5.0-11.0 wt-% cubic carbide forming metals selected from group IVb, Vb and VIb of the periodic table and balance WC, and with a weight-ratio of Ta and Nb, when present, between 1.0-3.0 and between Ti and Nb, when present, within 0.5-1.5 and with a coercivity (Hc) of 11.0-13.0 kA/m, and the cemented carbide is provided with a 10-30 μm, essentially cubic carbide phase free and binder phase enriched surface zone with average binder phase content in the range 1.2-2.5 times the nominal binder phase content; and
a coating comprising a MTCVD Ti(C,N) as a first layer adjacent the body having a thickness of from 2.5 to 7.0 μm, where the MTCVD-layer comprises an innermost TiN layer adjacent to the body with a Ti(C,N) layer on top, optionally with an additional intermediate TiN layer on top of the Ti(C,N) layer, with a thickness of 0.3-1.0 μm on top of which an α-Al 2 O 3 layer is present, with a thickness of between 2.0 and 5.0 μm and a total thickness of the coating between 5.5 and 9.5 μm, where the texture of the α-Al 2 O 3 layer is TC(006)>3.0 and where the texture coefficients (TC) for the α-Al 2 O 3 layer is determined as follows:
TC
(
hkl
)
=
I
(
hkl
)
I
0
(
hkl
)
[
1
n
∑
n
=
1
n
I
(
hkl
)
I
0
(
hkl
)
]
-
1
where
I(hkl)=intensity of the (hkl) reflection,
I 0 (hkl)=standard intensity according to JCPDS card no 46-1212, and
n=number of reflections used in the calculation, and the (hkl) reflections used are: (012), (104), (110), (006), (113), (202), (024) and (116), where TC(012), TC(110), TC(113), TC(202), TC(024) and TC(116) are all simultaneously <1 and TC(104) is the second highest texture coefficient with TC(104) between 0.5 and 2.0.
20. The cutting tool insert of claim 1 , wherein TC(006)=4.57 and TC(104)=1.32.Cited by (0)
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